Chaetopterus
Encyclopedia
Chaetopterus or the parchment worm or parchment tube worm is a genus
of marine
polychaete
worm that lives in a tube it constructs in sediments or attaches to a rocky or coral reef
substrate. The common name arises from the parchment
-like appearance of the tubes the worm lives in. Parchment tube worms are filter feeders and spend their adult lives in their tubes, unless the tube is damaged or destroyed. They are plankton
ic in their juvenile forms, as is typical for polychaete annelid
s. Species include the recently discovered deep water Chaetopterus pugaporcinus
and the well-studied Chaetopterus variopedatus
.
worms in the highly derived
parapodia
of the mid-segments of its body that are used in its specialized filter feeding regime. The worm's parapodia are modified into the shape of fans and used to created suction and pump water through the worm's parchment living tube. The morphology of the structures are used in identifying species. The worm feeds by using modified structures on its midbody segments that create mucus nets to trap food passed through the net. A flow of water containing plankton and organic debris is created by "circular flaps" on three segments that create suction that draws water through the living tube.
and live their entire adult lives in the their buried tubes. In spite of this, known members of the genera exhibit strong bioluminescence
. When the worm is disturbed in its home it moves to the end of the tube away from the disturbance and near the disturbance it emits its feeding mucous with crystals that exhibit blue luminescence.
) and Pinnixa chaetopterana
(family Pinnotheridae
); a third species, Tumidotheres maculatus
is known to sometimes inhabit the tubes. Polyonyx and Pinnixa are almost always present in the tubes, generally as a pair of crabs, and both species may inhabit the tubes at the same time. However, breeding pairs of either species do not share the tubes with adults of the other species. The crustaceans may live most of their lives in the tubes, leaving in the case of disturbance by exiting through the chimneys at either ends or, when the chimneys are too narrow, by biting through the parchment tube.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
polychaete
Polychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
worm that lives in a tube it constructs in sediments or attaches to a rocky or coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
substrate. The common name arises from the parchment
Parchment
Parchment is a thin material made from calfskin, sheepskin or goatskin, often split. Its most common use was as a material for writing on, for documents, notes, or the pages of a book, codex or manuscript. It is distinct from leather in that parchment is limed but not tanned; therefore, it is very...
-like appearance of the tubes the worm lives in. Parchment tube worms are filter feeders and spend their adult lives in their tubes, unless the tube is damaged or destroyed. They are plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
ic in their juvenile forms, as is typical for polychaete annelid
Annelid
The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...
s. Species include the recently discovered deep water Chaetopterus pugaporcinus
Pigbutt worm
The pigbutt worm or flying buttocks is a newly discovered species of worm found by scientists at the Monterey Bay Aquarium Research Institute. The worm is round in shape, approximately the size of a hazelnut, and bears a strong resemblance to a disembodied pair of buttocks...
and the well-studied Chaetopterus variopedatus
Chaetopterus variopedatus
Chaetopterus variopedatus is a species of parchment worm, a marine polychaete in the family Chaetopteridae. It is found worldwide.Polychaetes, or marine bristle worms, have elongated bodies divided into many segments. Each segment may bear setae and parapodia...
.
Housing tubes
The tubes the worms live in are either attached to rocks, or, more commonly, buried in sandy bottoms in shallow waters. The worm has spines along its body segments that are modified for tunneling into the sandy substrate to create the u-shaped tube within which it lives. The tubes are upright u-shaped tunnels lined with mucous, then the parchment tube, with the worm living inside the parchment tube. Each parchment tube ends with a chimney of parchment that juts above the subtrate. The tubes can be as long as 85 centimeters and up to 4 centimeters in diameter at the widest portion in the buried central part of the tube. The chimneys may be wide or much narrower than the rest of the tube.Worm morphology
The worms are unique among the polychaetePolychaete
The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...
worms in the highly derived
Derived
In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...
parapodia
Parapodium
Parapodia , singular parapodium, are paired, un-jointed lateral outgrowths from the bodies of two different invertebrate groups, which are primarily marine in habitat...
of the mid-segments of its body that are used in its specialized filter feeding regime. The worm's parapodia are modified into the shape of fans and used to created suction and pump water through the worm's parchment living tube. The morphology of the structures are used in identifying species. The worm feeds by using modified structures on its midbody segments that create mucus nets to trap food passed through the net. A flow of water containing plankton and organic debris is created by "circular flaps" on three segments that create suction that draws water through the living tube.
Bioluminescence
Members of the genus have no organs for detecting lightEye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
and live their entire adult lives in the their buried tubes. In spite of this, known members of the genera exhibit strong bioluminescence
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
. When the worm is disturbed in its home it moves to the end of the tube away from the disturbance and near the disturbance it emits its feeding mucous with crystals that exhibit blue luminescence.
Commensal crabs
Two species of filter-feeding crustaceans from different families may make their homes in the Chaetopterus tube, Polyonyx gibbesi (family PorcellanidaePorcelain crab
Porcelain crabs are decapod crustaceans in the widespread family Porcellanidae, which superficially resemble true crabs. They are typically less than wide, and have flattened bodies as an adaptation for living in rock crevices...
) and Pinnixa chaetopterana
Pinnixa chaetopterana
Pinnixa chaetopterana, the tube pea crab, is a small decapod crustacean that lives harmlessly within the tube of the polychaete worm, Chaetopterus variopedatus.-Description:...
(family Pinnotheridae
Pinnotheridae
Pinnotheridae is a family of pea crabs. Pea crabs are tiny soft-bodied crabs that live commensally in the mantles of certain bivalve molluscs...
); a third species, Tumidotheres maculatus
Tumidotheres maculatus
Tumidotheres maculatus is a species of crab that lives commensally or parasitically in the mantle cavity of molluscs. It is found along much of the western Atlantic Ocean and was first described by Thomas Say in 1818.-Distribution:...
is known to sometimes inhabit the tubes. Polyonyx and Pinnixa are almost always present in the tubes, generally as a pair of crabs, and both species may inhabit the tubes at the same time. However, breeding pairs of either species do not share the tubes with adults of the other species. The crustaceans may live most of their lives in the tubes, leaving in the case of disturbance by exiting through the chimneys at either ends or, when the chimneys are too narrow, by biting through the parchment tube.